pingback question

I have a pingback awaiting approval. The options are to approve, trash or mark as spam. I checked out the site and it's a grey area situation for me. Not spam, but should I select trash? IF I don't want that site to be added to my blog page url?

We aren't required to post pingbacks. I trash many of these each and every day.

IF I don't want that site to be added to my blog page url?

Nothing is being added to your URL. You cannot prevent anyone from linking to your posts but you are not compelled to post pingbacks. Posting a pingbacks in essense promote the liking site. Unless you feel they are sites that provide valuable resources to your readers don't approve them.